For the operation of automated or automatic change-speed transmissions in motor vehicles, in particular commercial vehicles, it is important to know the mass of the motor vehicle. Depending on the mass of the motor vehicle this enables shifting operations and starting processes to be carried out in a controlled or regulated manner.
From DE 10 2009 002 387 A1 it is known for a transmission control unit of a transmission to continually calculate the current mass of a motor vehicle during its operation, i.e. while driving, in particular with regard to topographical data concerning a current position of the motor vehicle. Such a calculation of the mass is only possible during driving operation, so that directly after a re-start of the motor vehicle or when the motor vehicle is at rest no calculation and thus no initialization of the mass of the motor vehicle is accordingly possible.
However, in the case of commercial vehicles such as semi-trailers, articulated vehicles or vehicles used on building sites, the mass can vary substantially due to loading and unloading operations at rest. To take account of such mass changes of the motor vehicle at rest, it is already known to estimate the mass of the motor vehicle when it is re-started or even at rest, and to update it so as to be able to better control or regulate a subsequent starting process on the basis of the initialized mass of the motor vehicle.
From DE 10 2009 046 344 A1 and DE 10 2007 015 536 A1 respective methods are known for initializing the mass of a motor vehicle. In each case this prior art relates to mechanisms for estimating the mass of the motor vehicle.
The methods known from the prior art for initializing the mass of a motor vehicle have the disadvantage that they carry out an initialization of the mass of the motor vehicle even if, while the motor vehicle is at rest, its mass has not changed because no loading or unloading processes have taken place. Thus, the mass of the motor vehicle estimated during initialization can differ substantially from the actual mass of the motor vehicle.